Fix spelling

docs/testing/phpunit.md

@@ -52,7 +52,7 @@ $ env CIVICRM_UF=UnitTests phpunit4 ./tests/phpunit/api/v3/CaseTest.php --filter
     You can also specify tests in an environment variable `PHPUNIT_TESTS` (eg. `env PHPUNIT_TESTS="MyFirstTest::testFoo MySecondTest" phpunit EnvTests`
     Then run `phpunit4 ./tests/phpunit/EnvTests.php`.
 
-You can also optionallly run a full standard CiviCRM Test suite by running `civi-test-run` as per example below
+You can also optionally run a full standard CiviCRM Test suite by running `civi-test-run` as per example below
 
 ```bash
 $ civi-test-run "<buildName>" "<civicrm version>" "<junit dir>" "<test-type>"